How to switch emmc boot0 / boot1 in andoridN

I have currently booted from emmc boot0, but I can't dynamically switch from emmc boot1 on the next boot.

I want to dynamically switch emmc boot0 or boot1 to start, but the trouble I am having now is that I can't switch emmc boot1 such as echo 1 > ../bootcomfig, and there is no mmc command in the system. My kernel version is 4.9, AndroidN imx6qp platform.